At present, there is a constant need for additional methods to utilize solid fuels such as coal, but minimize emissions of noxious gases that may arise from the fuel's combustion. This invention is directed to overcoming past problems in obtaining clean and safe fuels and providing methods for reducing or eliminating the emission of noxious gases such as NOx when combusting fuels such as coal, wood or biomass.
This invention centers around methods for effectively and efficiently delivering catalyst materials to the surface of a solid fuel maintaining the catalyst in relation to the solid fuel such that the catalyst is available at the earliest stages of combustion of the solid fuel. The catalysts are most effective at reducing noxious emissions such as NOx when available in the earliest stages of the combustion process. It is also important to ensure maximum contact between the catalyst and the combustion gases. In general, these catalysts which can be referred to as chemical change agents may contain functional groups which are chemically active and which can combine with coal to bring about a compositional changes and result in the reduction and/or elimination of noxious gases such as NOx.